Winter Storm Warning
Encyclopedia
A Winter Storm Warning is a statement made by the National Weather Service
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...

 of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 which means a winter storm
Winter storm
A winter storm is an event in which the dominant varieties of precipitation are formed that only occur at low temperatures, such as snow or sleet, or a rainstorm where ground temperatures are low enough to allow ice to form...

 is occurring or is about to occur in the area, usually within 24 hours. Generally, a Winter Storm Warning is issued if at least 4 inches (10.2 cm) to 7 inches (17.8 cm) or more of snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...

 or 3 inches (7.6 cm) or more of snow with a large accumulation of ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...

 is forecast. In the Southern United States
Southern United States
The Southern United States—commonly referred to as the American South, Dixie, or simply the South—constitutes a large distinctive area in the southeastern and south-central United States...

, where severe winter weather is much less common and any snow is a more significant event, warning criteria are lower, as low as 2 inches (5.1 cm) in the southernmost areas. A warning can also be issued during high impact events of lesser amounts, usually early or very late in the season when trees have leaves and damage can result.

Usually, a large accumulation of ice alone with no snow will result in an Ice Storm Warning
Ice Storm Warning
An Ice Storm Warning is issued by the National Weather Service of the United States when freezing rain produces a significant and possibly damaging accumulation of ice...

, or in the case of light freezing rain, a Winter Weather Advisory
Winter Weather advisory
A Winter Weather Advisory is issued by the National Weather Service of the United States when a low pressure system produces a combination of winter weather that presents a hazard, but does not meet warning criteria. A Winter Weather Advisory is similar to significant weather advisory, but a...

, a Freezing Rain Advisory
Freezing rain advisory
A Freezing Rain Advisory is an advisory issued by the National Weather Service in the United States when freezing rain or freezing drizzle is expected to cause significant inconveniences, but does not meet warning criteria .-Example: Freezing Rain AdvisoryURGENT - WINTER WEATHER...

, or Drizzle Advisory.

A similar warning is issued by Environment Canada
Environment Canada
Environment Canada , legally incorporated as the Department of the Environment under the Department of the Environment Act Environment Canada (EC) (French: Environnement Canada), legally incorporated as the Department of the Environment under the Department of the Environment Act Environment...

's Meteorological Service of Canada
Meteorological Service of Canada
The Meteorological Service of Canada , also known as "The Canadian Weather Service", is a division of Environment Canada, which primarily provides public meteorological information and weather forecasts and warnings of severe weather and other environmental hazards...

from their offices.

Prior to the 2008-09 winter season, there was the Heavy Snow Warning, specific for when only a heavy amount of snow was expected in the warned area. The Winter Storm Warning for Heavy Snow has since replaced it.

Example of a Winter Storm Warning


URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORTHERN INDIANA
236 PM EST MON JAN 31 2011

...POWERFUL WINTER STORM TO AFFECT THE REGION...

.AN INTENSE WINTER STORM WILL MOVE THROUGH THE AREA IN TWO PHASES
BEGINNING TONIGHT AND ENDING WEDNESDAY EVENING WITH A LULL TUESDAY
MORNING. SNOW WILL DEVELOP ACROSS THE AREA EARLY THIS EVENING WITH
A MIX OF SLEET AND SNOW EXPECTED MAINLY SOUTH OF HIGHWAY 24. SNOW
ACCUMULATIONS TONIGHT WILL BE GENERALLY 2 TO 5 INCHES...WITH
LESSER AMOUNTS WHERE THE MIX OCCURS AND IN THE FAR NORTH. WINDS WILL
INCREASE EARLY TUESDAY WITH BLOWING AND DRIFTING SNOW...ALTHOUGH
THERE WILL LIKELY BE A LULL WITH THE FALLING SNOW TUESDAY MORNING
AND EARLY TUESDAY AFTERNOON.

HEAVY SNOW WITH SIGNIFICANT BLOWING AND DRIFTING IS LIKELY BY
LATE TUESDAY AFTERNOON. VERY HEAVY SNOW WILL CONTINUE TUESDAY
NIGHT INTO WEDNESDAY MORNING...ENDING BY WEDNESDAY EVENING.
SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR ARE EXPECTED TUESDAY
NIGHT. SNOW MAY MIX WITH OR CHANGE TO SLEET OR FREEZING RAIN
SOUTH OF ROUTE 24...WITH SIGNIFICANT ICING POSSIBLE. ICE
ACCUMULATIONS WILL LIKELY BE BETWEEN ONE QUARTER AND ONE HALF
INCH...WITH HIGHEST ICING POTENTIAL NEAR AND SOUTH OF A LINE FROM
MARION INDIANA TO OTTAWA OHIO. SNOWFALL AMOUNTS OF UP TO 18 INCHES
WILL BE POSSIBLE WITH THIS SYSTEM...WITH LOCALLY HIGHER AMOUNTS OF
OVER 20 INCHES NOT OUT OF THE REALM OF POSSIBILITY. THESE HIGHER
SNOWFALL AMOUNTS WILL BE ACROSS FAR NORTHERN INDIANA AND SOUTHWEST
LOWER MICHIGAN.

SUSTAINED WINDS OF 15 TO 30 MPH WITH HIGHER GUSTS...WOULD SUPPORT
WIDESPREAD BLOWING AND DRIFTING SNOW...WITH DRIFTS POTENTIALLY
REACHING SEVERAL FEET IN SOME LOCATIONS. BLIZZARD TO NEAR
BLIZZARD CONDITIONS ARE ALSO POSSIBLE IN MANY AREAS...ESPECIALLY
ACROSS FAR NORTHWESTERN INDIANA AND SOUTHWEST LOWER MICHIGAN.
VISIBILITIES COULD BE DOWN TO ZERO AT TIMES TUESDAY NIGHT AND
WEDNESDAY MORNING. TRAVEL WILL LIKELY BE DIFFICULT TO IMPOSSIBLE
IN MANY AREAS...WITH ROAD CLOSURES POSSIBLE.

LISTEN TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA FOR UPDATES ON
THIS DANGEROUS WINTER STORM...ESPECIALLY IF YOU ARE PLANNING
TRAVEL IN THE REGION.

INZ017-018-022>027-032>034-OHZ004-005-015-016-024-025-010400-
/O.UPG.KIWX.WS.A.0001.110201T0000Z-110203T0000Z/
/O.NEW.KIWX.WS.W.0001.110201T0000Z-110203T0000Z/
WHITLEY-ALLEN IN-CASS IN-MIAMI-WABASH-HUNTINGTON-WELLS-ADAMS-
GRANT-BLACKFORD-JAY-DEFIANCE-HENRY-PAULDING-PUTNAM-VAN WERT-
ALLEN OH-
INCLUDING THE CITIES OF...COLUMBIA CITY...TRI-LAKES...
SOUTH WHITLEY...FORT WAYNE...NEW HAVEN...LOGANSPORT...
ROYAL CENTER...PERU...GRISSOM AFB...MEXICO...WABASH...
NORTH MANCHESTER...HUNTINGTON...ROANOKE...BLUFFTON...OSSIAN...
DECATUR...BERNE...MARION...GAS CITY...UPLAND...HARTFORD CITY...
MONTPELIER...PORTLAND...DUNKIRK...DEFIANCE...SHERWOOD...
HICKSVILLE...NAPOLEON...DESHLER...LIBERTY CENTER...PAULDING...
ANTWERP...MELROSE...OTTAWA...PANDORA...KALIDA...FORT JENNINGS...
VAN WERT...DELPHOS...OHIO CITY...LIMA...SPENCERVILLE
236 PM EST MON JAN 31 2011

...WINTER STORM WARNING IN EFFECT FROM 7 PM THIS EVENING TO 7 PM
EST WEDNESDAY...

THE NATIONAL WEATHER SERVICE IN NORTHERN INDIANA HAS ISSUED A
WINTER STORM WARNING FOR A MIX OF SNOW...SLEET AND FREEZING RAIN...WHICH
IS IN EFFECT FROM 7 PM THIS EVENING TO 7 PM EST WEDNESDAY. THE
WINTER STORM WATCH IS NO LONGER IN EFFECT.

  • TIMING...SNOW WILL DEVELOP TONIGHT. AFTER A SHORT LULL IN THE

SNOW TUESDAY MORNING...THE SNOW WILL EXPAND IN COVERAGE AND
INTENSITY LATE TUESDAY. SNOW MAY MIX WITH OR CHANGE TO FREEZING
RAIN AND SLEET LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. SNOW
WILL CONTINUE INTO WEDNESDAY AFTERNOON...ENDING WEDNESDAY
EVENING.
  • MAIN IMPACT...2 TO 5 INCHES OF SNOW WILL BE POSSIBLE BY TUESDAY

MORNING. ADDITIONAL HEAVY SNOW AND SLEET ACCUMULATIONS OF 4 TO 8
INCHES ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY. IF
PRECIPITATION CHANGES TO FREEZING RAIN OR SLEET...MUCH LOWER
SNOWFALL AMOUNTS WOULD BE EXPECTED BUT SIGNIFICANT ICING WOULD
BE POSSIBLE WITH EXTENDED POWER OUTAGES. ONE QUARTER TO ONE HALF
INCH OF ICE ACCUMULATION IS POSSIBLE.
  • OTHER IMPACTS...SUSTAINED WINDS OF 15 TO 30 MPH WITH HIGHER

GUSTS WOULD SUPPORT WIDESPREAD BLOWING AND DRIFTING SNOW...
HIGHLY IMPACTING TRAVEL. THESE WINDS WOULD ALSO CAUSE TREE LIMBS
AND POWER LINES TO FALL IF SIGNIFICANT ICING OCCURS.
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW...
SLEET...AND ICE ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO
POSSIBLE. THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

&&

$$

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